Seizure Lecture Flashcards
Paroxysmal event due to abnormal CNS discharge with resultant manifestations
5-10% of gen pop will have
More prevalent in childhood and later adulthood
Seizure
2 big classes of seizures?
Partial
Generalized
Deranged area of cerebral cortex, often due to a STRUCTURAL ANOMALY most commonly
usually no LOC (but some exceptions)
Partial seizure
2 classes of partial seizures?
- Simple (NO LOC)
- Complex (LOC)
Diffuse region of brain firing simultaneously
often due to WIDESPREAD problem
(ie.. cellular disorder, biochemical disruption, structural issue)
Generalized seizure
NO LOC**
EEG shows abnormal impulses in FOCAL area of brain*
Often clonic with repetitive flexion/extension
(ie..may get hand tremor on opposite side of abnormal brain activity)
Simple partial seizure
Jacksonian March
Todd’s Paralysis
Epilepsia Partialis Continua
..subcategories of which type of seizure?
Simple partial seizure
Motor activity begins distally (i.e. fingers) and spreads to whole extremity
..this describes which subcategory of simple partial seizures?
Jacksonian March
Local paresis that can last minutes to hours
..this describes which subcategory of simple partial seizures?
Todd’s paralysis
- Changes in somatic sensation (parasthesias)
- Change in vision
- Change in equilibrium
- Autonomic changes (flushing, sweating)
More symptoms seen in…..
Simple partial seizures
FOCAL activity progresses to loss of contact with environment (ictal state)
*stare
*amnesia
Complex partial seizures
Often begins with aura Followed by ictal state:
involuntary behaviors, picking, chewing
*can last seconds to hours
Complex partial seizures
Partial seizures that occur in the FRONTAL LOBE are more likely to have….
secondary generalization
A seizure that begins as a partial seizure
electrical discharge spreads and both hemispheres become involved
*results in TONIC CLONIC seizure
Partial seizure with secondary generalization
*common when partial seizures are in the frontal lobe
Arise in both cerebral hemispheres simutaneously
include: Absence and Tonic-Clonic
Generalized seizures
brief LOC without postural control
usually lasts a few seconds
NO POST ICTAL STATE
other subtle findings:
Eye blinking, chewing, clonic movements of hands
Absence seizure
Onset is childhood
4-8 yo or early adolescence
account for 15-20% of childhood seizures
“day dreaming” or ADD like presentation
Absence seizure
EEG will show symmetrical discharge
spikes and waves
will worsen with hyperventilation maneuver*
Absence seizure
Grand mal
10% of patients with epilepsy
MC type of seizure due to metabolic derangement
*suddent onset!
Tonic-clonic seizure
Increased muscle tone
Cry out/moan
Secretions pool
Cyanosis
Jaw clenches, can bite tongue
Sympathetis sxs: increase in BP and HR, pupil dilation
..which phase of a tonic-clonic seizure?
Tonic phase
Muscles relax and contract
usually lasts about 1 minute
..which phase of a tonic-clonic seizure?
Clonic phase
Unresponsive
Flaccid
Salivation or airway obstruction
Incontinence
Which phase of tonic-clonic seizure?
Post ictal phase
*can be mins to hours before awakening
Headche
Fatigue
Muscle aches
..what phase of a tonic-clonic seizure?
Post seizure
EEG showing:
Increased low voltage fast activity
High amplitude polyspike discharges
..which phase of tonic-clonic seizures?
Tonic phase
EEG showing:
Spike and wave activit develops
..which phase of tonic-clonic seizure?
Clonic
EEG showing:
slowing then recovery
..which phase of tonic-clonic seizure?
Post-ictal
Atonic and Myoclonic seizures are variations of…
Tonic-clonic seizures
A variation of T-C seizures
1-2 seconds loss of motors tone
brief LOC
no post ictal confusion
Atonic seizures
A variation of T-C seizures
brief contraction or jerk
seen in brain injuries
(the movement you get before you fall asleep)
Myoclonic
Juvenile Myoclonic Epilepsy
Lennox Gastaut Syndrome
Mesial Temporal Lobe Epilepsy
…subcategories of what type of seizures?
Generalized seizures
Seen in adolescence
bilateral jerk without LOC
*worse with awakening and sleep deprivation
*benign..good response to tx. often self resolve
Juvenile Myoclonic
Multiple types…seen in children
Associated with CNS disease:
Developmental delay
Trauma
Infection
Neural injuries
*usually impaired cognitive function
Lennox Gastaut
Partial epilepsy with characteristic features
MRI shows hippocampal sclerosis***
Mesial temporal
Shift in balance of excitation and inhibition in CNS
Mechanisms:
Change in threshold (ie fevers)
Genetics
Traumatic brain injury
Other events: stroke, infections
Other factos:
-stress, sleep deprivation, menses, meds
Etiology of seizures
Burst of electrical activity..influx of extracellular calcium*
Exctiatory moleciles, like NMDA may further Ca influx
Spike discharge
Inhibitory neurons overwhelmed by Ca and K
Propogation of APs
What goes on during a seizure
birth injury
congenital abnormalities
maternal drug use
..causes of seizures in?
Neonates
MC cause of early childhood seizures?
Fever!
(febrile seizures)
usually occurs 3mos to 5 years
often caused by:
otitis media, respiratory infection, gastroenteritis
recurrence occurs in about 1/3 of patients
Febrile seizures
When does epilepsy become apparent?
During childhood
What must you think about if an adolescent has a seizure?
Trauma!
*worse trauma= worse seizures
What is the cause of 50% of new onset seizures in adults?
Cebrovascular disease
Cerebrovascular disease
Trauma
CNS tumor
Degenerative disease
Medical (hypo/hyper glycemia, renal failure, liver dz, drugs)
Causes of seizures in adults
Which one is inhibtory? Which one is excitatory?
- Glutamate
- GABA
Glutamate= excitatory
GABA= inhibitory
(seizure meds target these)
Alpha: 8-13 Hz
Beta: >13 Hz
Theta: 4-7 Hz
Delta: <4 Hz
..these can be determined by which diagnostic?
EEG
- Awake/sleep
- Eyes open/closed or with photo stimulation
- Hyperventilation
- Sleep deprivation
..all of these states should be assessed with?
EEG
Abnormal activity that starts/stops abruptly
Abnormal activity during T-C seizures
Inter-ictal may see sharp spikes or waves (40%)..worse prognosis
Key findings on EEG
EEG
Imaging (MRI=best!!)
Blood test (usually norm, prolactin may be increased within first 30 mins)
Work up for seizure
Block activity of ion channels or neurotransmitters
Inhibit Na dependent APs
Inhibit Ca channels
Decrease glutamate release
Increase GABA availability
Mechanisms that seizure meds work
Blocks voltage dependent calcium channels, modulating excitatory neurotransmitter release
Gabapentin or Pregabalin?
Gabapentin
Binds alpha2-delta subunit of calcium channels, decreasing NT release,
producing anti-nociceptive and anti-seizure effects
Gabapentin or Pregabalin?
Pregabalin
When would you take a pt off seizure meds?
How would you do it?
Can try taking off if:
Low risk
1 seizure then seizure free
Normal exam
Normal EEG
must take off meds slowly! taper!
Continuous seizure
(seizures follow one another without recovery of consciousness between)
Some say if more than 15-30 mins
Others if > 15 seconds
May range from T-C seizure to more subtle (finger or eye movement)
May need EEG to verify
Status epilepticus
Medical emergency!
Cardiovascular implications
Hyperthermia
Metabolic derangements
CNS injury
Status epilepticus
Metabolic problems
Drug toxicity
CNS infection or tumor
Head injury
Refractory epilepsy
..can all cause?
Status epilepticus
How do you stop/treat status epilepticus?
Benzos!
Phenytoin
Phenobarbital
What does a vagal nerve stimulator do?
Increase seizure threshold
(this is a bipolar electrode in the left vagal nerve)
Seizures characterized by an aura, followed by impaired consciousness lasting seconds to minutes
N/V, focal sensory preceptions and focal tonic or clonic activity may accompany
Complex partial
EEG will show spike and wave activity
Absence seizure
(Tonic clonic seizures will have generalized rapid spiking)
